No abstract

Films of Kraton G-1650, a styrene-(ethene-co-butene)-styrene triblock copolymer, have been cast from a variety of solvents with solubility parameters in the range 15.1 to 20.5 (J m-3)1/2. The complex modulus E*, measured at 298 K, was found to vary from 4.4 X 106 N m-2 for films cast from low solvents to 2.05 X 10s N m"2 for films cast from high solvents. The areas under the damping peaks in the dynamic mechanical spectra were also altered by the casting solvent, which influences the manner in which the two component blocks are distributed in the solid state. Evidence of limited crystallinity in Kraton-G was found using differential scanning calorimetry and this was also used to estimate the heat capacity changes ACP for the glass transitions associated with each block. These were always found to be less than that expected for the pure component.

The miscibility of poly(viny1 chloride) with poly(methy1 methacrylate-stat-acrylonitrile) has been studied. Poly(viny1 chloride) is miscible with methyl methacrylate/acrylonitrile copolymers having acrylonitrile contents between 2,O and 17 wt.-Yo. All calculated binary segmental interaction parameters were positive, suggesting immiscibility of the corresponding binary homopolymer blends.